Method of manufacturing rubber articles



Patented Aug. '9, 1932 UNITED STATES;

immree ee DOUGLAS FRANK-TWISS, or vvYitnE GB-EEN, FRANK THEODORE roams,on MOSELEY,

AND EDWARD ARTHUR. MURPHY, OF WYLDE GREEN,'ENGLAND,"ASSIG:1\TOBS' TODUNLOP RUBBER COMPANY LIMITED, 01? BIRMINGHAM, EIJN'GrLAND, ACORPORATION,

OF GREAT BRITAIN,

METHOD OF MANUFAC[CURING RUBBER ARTICLES No Drawing. Application filedSeptember 17, 1929, Serial No. seaaca ana in Great Britain October 1a,1928.

This invention concerns improvements in the manufacture of rubberartlcles and 1s of such articles by the gelling of concentrated' aqueousdispersions of. rubber or the like vegetable resins.

lhe object of the invention is the manufacture of articlesof rubber bythe gelling of latex, the .gelling being produced by the heating oflatex in which are incorporated small quantities of one or morenon-coagulating sustances which decompose or interact by therise intemperature with the forma- H tion of oneor more acid coagulants forlatex.

fr-Xcco'rding to one form of the invention ammonium persulphate andtrioxyniethylene are incorporated into concentrated compounded latexhaving a water content of 10% to 40% in the order of 0.1% of eachingredient. The mixture thus produced is quite stable but on heatingsuch a mixture to 90 C. for a few minutes the mixture gels to a masswhich can be dried Without loss of shape althou h shrinka e naturall Ioccurs. t)

' its transformation and itself undergoing oXidation to formic acidWlllClllS, as is well known, also a coagulating agent for latex.

The concentrated dispersions of rubber or the like vegetable resins maybe compounded, preserved, natural or artificial, vulcanizedorunvulcanized andsuch dispersionsmay also contain such added substancesas factice, rubber waste, rubber reclaim, mineral rubber or syntheticrubber, vulcanizing agents accelerators, additional preservatives, dyesand filling materials of the ordinary type as'well as such specialmaterials as leather dust, cork dust, fibres, metal dust and colloidalmetals. Such dispersions may also have admixed therein such artificialresins as phenol-aldehyde, protein-aldehyde and condensation products.

Suitable mixes in the form of aqueous dishave been found suitable vEwample I: 7 Rubber as latex 35. Sulphur 2.

Accelerator O. Whiting 13. Zinc oxide; 3. Barytes 20- Transformer oil 5.Colour i 0. Ammonium persulphate A O. 'Trioxymethylene i O.

e V 100. O v r v Ewample [I Rubber as latex 97. O Sulphur 2 1Accelerator 0. 5

. Ammonium persulphate O. 2 Trioxymethylene 0. 2

As a modification of the above process ammomum persulphate may be usedalone or with the addition of-other' substances such if as formaldehyde,acetaldehyde, paraformaldehyde, paraldehyde and of any other suchorganic substance of substantially neutral reactioncapable of oxidationto an acidic substance or substances; ammonium thiosulphate or ammoniumsalts of other sulphur acids capable ofyielding oxidationproducts ofgreater acidity, e. g. dithionatemay also be used in conjunction withammonium per- Ammonium piersulphate urea-aldehyde HHOOQQOO-I-POOI Inanother form of'the invention ammonium thiosulphate or bariumthiosulphate may be used in conjunction withsome sub stantiallynon-coagulating oxidizing agent.

' Ammonium persulphate has already been mentioned in this connectionneutral salts of per-acids generally and or hydrogen per-' oxide canalso be usedwithammonium thio-- sulphate to-yield acidic reactionproducts as the result of mutual interaction.

In yet another form the chemical process for the development of aciditymay not involve oxidation. Thus ammonium thiosuh phate or bariumthiosulphate may be used portion of a salt,.e. g. lead acetate (insufficient proportion to cause premature coagulation) which acceleratesdecomposition of the thiosulphate radical withformation of acidicproducts. a 7

Various modifications may be made by those skilled in the 'art withoutdeparting from the inventionas'defined in the appendedclaims .What weclaim is: ,1

1. A process for the manufacture of rubber articles from concentratedaqueous dispersions ofrubber' or the like egetable resins of the kindshereinbefore specified whichconis in gelling by the act on he t h -aqous spersion afore id into whi h e 1 1- corporated for theparticularpurpose specifle on r mor non-coagulat g sub tance whichdecompose or interact bythe rise in temperature with the formation ofone or more acid coagulants.

2. A process as claimed in claim 1, wherein are incorporatedwith theaqueous-dispersion aforesaid ammonium persulphate and trioxymethylene.

; 8. A process as claimed in claim 1, wherein are lncorporated lntoconcentrated compounded latex having a water'content of 10% alone or'inconjunction with a small pro-' 1,870,788 ns a sions aforesaid athiosulphate and neutral salts of a per-acid.

8. A process as claimed in claim 1, wherein isincorporated with theaqueous dispersions aforesaid a thiosulphate;

9. A process asclaimed-in claim 1, wherein is incorporated with theaqueous dispersion aforesaid, a thiosulphate and .a small quantity ofasalt in insufficient portion, to

cause premature coagulation, which accelerates decompositionof the'thiosulphate radical with formation of acidic products.

, 10. A composition of matter including latex in which are incorporatedsmall quantities ofammonium 'persulphate and an :organic substance ofsubstantially neutral reaction capable of oxid'ationto an acidicsubstance; 1 q 11'. A composition of matter'including'later: in whichare incorporated small quantiproducts.

{In witness whereof, we have hereunto signed our names. I A 1 DOUGLrfSFRANK TWISS..- FRANK THEODORE PURKIS. EDWARD ARTHUR MURPHY.

to 40%amm'on'ium p'ersulphate andtri-oXyv by heating to 90 C. for ELLfGWminutes. a 4. A process as claimed in claim 1, wherein methylene in theorderof 0.1%fof each-ingredient' and eflecting thegelling of the mixtureis incorporated with the aqueous-dispersion aforesaid ammoniumpersulphate. I

5. A process as claimedin claim'l, wherein is incorporated withtheaqueous dispersion aforesaid ammonium persulphate and sub- 1 stances of"substantially neutral reaction capable of oxidation to an acidicsubstance or substances.

6. A process as claimed in" claim lgiwhereiin is incorporated with theaqueousdispersions aforesaid ammonium p ersulphate and an ammonium saltof other sulphur iaci'ds fc'a'pabl'e' of yieldingcxidation' productsoffgreater acidity.

A process as aaaaa eiaimi; amen ,1 ai is incorporated with the aqueousdisper-

